Rubber-bands on RD4B

I have tried different ways of using rubber bands on my RD4B with a 6 bar on top and all have still left a lot of tension on my motors. I have several pictures with their arrangement. The lower half of my rubber-banding for me at least seems to be perfect, but I can’t quite get the top 6 bar to behave properly. Any suggestions would be helpful.
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You really only have to rubber band one part of the lift, either the top or the bottom. I chose to do the bottom because I found that it helps to counteract the lift’s natural slop that causes it to lean forward at times.

While the general shape of the triangle you form doesn’t matter all too much (so long as it always keeps the rubber bands tense), I like to have an arrangement that makes the bands make an equilateral triangle when the lift is all the way up. This makes sure that all parts of the rubber bands have even tensions, just in case they get caught somewhere and can’t naturally even their tensions out.

The single biggest thing that I can recommend to you (and to every other team that doesn’t already do this) is to rubber band both sides of the metal. 99% of teams just rubber band one side, and over time it will cause torsion on your bars, which means that any gears attached to those bars will also warp, causing extra friction that will slow your lift down and make it stall faster. Most people think that they can’t rubber band both sides of their metal due to spacing issues (like how rubber banding the inside parts of the bottom bars could hit the top bars when the lift moves down), but trust me, it can be done with ample clearance. I like to use the green pulleys on both sides, which leaves 1/16" of clearance between the pulley and the other bar when the lift moves down. Some people aren’t comfortable with this, so in this case I’d suggest using pulleys on the outsides and slightly shorter standoffs on the insides. You naturally have 1/2" of space between the bottom and top bars with normal spacing, so you should be able to make it work.

tl;dr --> Only rubber band the bottom, and please rubber band both sides of the metal. Good luck!

I do not have any green sliders and not enough clearance to be able to lift upwards and not hit the upper bars. So I have no clue what to do.

Based on your pictures, I’d say you actually do have the clearance. Your lift seems to be spaced normally, so you have exactly 1/2" of space (the width of the gears that your bars are attached to). If you don’t have the green pulleys, then grab some 1/4" standoffs or something. It’s 100% worth making sure you can rubber band both sides, because your lift will behave much smoother if you can.

If there’s really no way, then my only other suggestions are to (again) just rubber band the bottom bars, and to make the banding approach an equilateral triangle as the lift goes up.

Have you also considered the possibility that your lift may not be behaving because of how heavy it is? Based on your pictures it looks like a 2 motor lift, and I can’t imagine a full six bar on top made out of full c channel (most people usually use half cuts to cut down a lot on weight) being easy on the motors.

I think I’ll probably just add a c-channel on the side of lower lift to lower the stress and bending and only rubber band the bottom. But as for weight, we did not have enough experience with doing 1x1s and little time, but many other teams also have full c-channels on their top section. 86868R for example when we saw them in our state.

Here is my solution and it has fixed the problems with my lift. My motors are no longer overloaded by weight. In case anyone wanted to know my solution.
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